An architecture trying to respond a least 10000 concurrent connections per second, is trying to solve the C10K problem, even if this is so last decade is still breaking servers, architectures and configurations, giving to sysadmins real headaches and not always because of real connections, also for basic DDoS attacks (pretty much is the same concept: lots and lots of new connections to the same service).

It’s not a secret that the best and most competitive technologies today exist in the world are based on some Open Source component, maybe the Linux kernel, GNU/Linux operating system, a version of BSD, modules, drivers, or the programming language is completely free or have a free compiler or interpreter.

Aug 10 2012

Free EL YUM Repositories

If you are using some flavor of an Enterprise Linux, eventually will get tired of download rpm packages from Here BTW, is a really great page when you don't have access to FTP services (damn telecom/security guys).

And eventually, you will need to have repositories on your server to solve the dependencies.
Here are some free repository provided by Oracle for FREE, but of course, with NO SUPPORT.

Jul 4 2012

New user created as:

groupadd mygroup
useradd -s /bin/bash -g myuser -m -k /dev/null myuser

When trying to log in:

[root@vserver~]# su - myuser
su: /bin/bash: Permission denied

Solution:

[root@vserver~]# chmod 755 /bin
[root@vserver~]# su - myuser
[myuser@vserver~]$
Apr 24 2012

Supose you want to use Linux and OpenSSH to automize your tasks or you just don't want to type the password everytime you connect to a server.
You can solve this issue by doing this.

Scenario:
skyline wants to connect to veyron using ssh without password.

By default the ssh command has an order to check for autentications: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password

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Apr 10 2012

Headup Portage Tree

This portage tree is for apps that are not inside the official portage repository and some other packages with some hacks.
If you would like to contribute, report some bugs or send me suggestions, you can send me an email: alvaro[at]headup[dot]ws

Starting Points

Apr 5 2012

As a sysadmin, I need to generate lots of passwords and sometimes if you do so without an script the generated password becomes really easy to guess and also is hard to build a safe password.

Because of this I use this script to generate pseudo randomly passwords, is not an un-crackable method but solves the main problem.
You can put this code at the end of your .bashrc file, in order to make it like a system command, please do not remove the other lines in the file.

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Apr 3 2012

Subversion is a software versioning and revision control system.
Every copy of source code received from subversion repository has .svn folders, which store metadata.

This is a simple example of a unix command, which recursively deletes subversion .svn folders, these folders are often not necessary, if you want to distribute the source code.
You can put this code at the end of your .bashrc file, in order to make it like a system command, please do not remove the other lines in the file.

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I'm using an old kernel because is the last stable to use with VServer patch.

Dec 21 2011

First, Check you squid.conf file and locate the location of you cache directory, you should have line starting with "cache_dir"

1) Shutdown your squid server
squid -k shutdown

2) Remove the cache directory
rm -r /squid/cache/*

3) Re-Create the squid cache directory
squid -z

4) Start the squid

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